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Relationship between phosphatidylinositol synthesis and recovery of 5-hydroxytryptamine-responsive Ca2+ flux in blowfly salivary glands.

ABSTRACT: Each salivary gland contains about 135 pmol of phosphatidylinositol. In glands prelabelled by incubation for 1 h with [32P]Pi or [3H]inositol there was a subsequent breakdown of 80% of the labelled phosphatidylinositol over a 2 h incubation period with 10 micrometer-5-hydroxytryptamine. However, there was no detectable decrease either in total phosphatidylinositol based on phosphorus analysis by chemical estimation or in the radioactivity of [32P]phosphatidylinositol in salivary glands of flies raised from the larval stage on diets containing[32P]Pi and whose phospholipids were uniformly labelled. These results suggest that the pool of phosphatidylinositol involved with Ca2+ gating is a small fraction of the total phosphatidylinositol content. Furthermore it is this small compartment that is preferentially radioactively labelled during short-term incubations with radioactively labelled precursors. In salivary glands incubated for 2 h with 10 micrometer-5-hydroxytryptamine there was a marked decrease in the flux of 45Ca2+ across the gland. After removal of the hormone, incubation of salivary glands for 1 h in the presence of 2mM-inositol, but not choline or ethanolamine, resulted in a recovery of hormone-responsive 45Ca2+ flux. Quantitative studies revealed that less than 9 pmol of phosphatidylinositol must be formed to fully restoret he 5-hydroxytryptamine-responsive 45Ca2+ flux.

SUBMITTER: Fain JN

PROVIDER: S-EPMC1161106 | biostudies-other | 1979 Jun

REPOSITORIES: biostudies-other

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Phosphoinositide synthesis and Ca2+ gating in blowfly salivary glands exposed to 5-hydroxytryptamine.

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Senseless-responsive and GAL4-responsive genes in larval salivary glands of late Drosophila prepupae

Project description:This SuperSeries is composed of the SubSeries listed below.

2008-05-29 | GSE8623 | GEO

GAL4-responsive genes in larval salivary glands of late Drosophila prepupae

Project description:The yeast transcription factor GAL4 has been reported to cause cell death and to have other biological effects when expressed in Drosophila (Kramer and Staveley, 2003: Genet. Mol. Res. 2, 43; Rezaval et al., 2007: Eur. J. Neurosci. 25, 683). Using heat-shock-induced expression of GAL4 to drive expression of a UAS-senseless responder gene in transcriptional profiling experiments, we found that the underlying cause of these effects might be a genomic response to GAL4. To further characterize this response and to account for GAL4-independent changes caused by the transgene integration, GAL4 was expressed from two copies of the transgene in two independent lines, P{GAL4-Hsp70.PB}89-2-1 (short P{hs-GAL4}89) and P{hs-GAL4}X1. In addition, GAL4 was expressed from only one copy of the transgene in P{hs-GAL4}89 prepupae to account for the dosage dependence of observed effects. Prepupae carrying the hs-GAL4 transgenes were subjected to a 30-min heat shock treatment (37 °C) at 9 hours after puparium formation. RNA was isolated from salivary glands dissected from these and similarly treated w1118 control animals at 14 hours after puparium formation and subjected to microarray analysis with Affymetrix GeneChips. The microarray data identified an overlapping set of 1,009 genes that showed an at least 1.5-fold change in expression in both of the GAL4-expressing lines, defining a core set of GAL4-responsive genes in the salivary glands. This set includes genes involved in the control and execution of programmed cell death and in other important regulatory pathways. Keywords: ectopic expression experiment

2008-05-29 | GSE8620 | GEO

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